function ajax(url, vars, callbackFunction){
        if (window.XMLHttpRequest) {
                var request = new XMLHttpRequest();
        } else {
                var request = new ActiveXObject("MSXML2.XMLHTTP.3.0");
        }
 
        request.open("POST", url, true);
        request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); 
 
        request.onreadystatechange = function(){
 
                if (request.readyState == 4 && request.status == 200) {
 
                        if (request.responseText){
 
                                callbackFunction(request.responseText, (typeof(request.responseXML) != undefined)? request.responseXML:"");
                        }
                }
        }
        request.send(vars);
}